Association of FOBT-assessed faecal Hb content with colonic lesions detected in the Florence screening programme

We assessed the correlation between quantitative results of immunological faecal occult blood testing (I-FOBT) and colonic lesions (191 colorectal cancers, 890 adenomas) detected at colonoscopy in 2597 FOBT+ (cutoff 100 ng ml−1 Hb) subjects. At univariate analysis, a higher average faecal Hb content was significantly associated with male gender (P=0.003), age (P=0.02), and colonoscopy findings (P=0.000). Among adenomas, higher faecal Hb content was significantly associated with size (P=0.0000), presence of severe dysplasia (P=0.0001), presence of villous component (P=0.0002), and location in the left colon (P=0.003). At multivariate analysis adjusting for potential confounders, age (P=0.03), size (P=0.0000), and location in the left colon (P=0.0005) were confirmed as having an independent association with higher faecal Hb content. Immunological FOBT is confirmed to be a specific screening test to detect cancer and adenoma, with a low positivity rate (3.7%) and a high positive predictive value (41.5%). Faecal Hb content is significantly higher for those lesions (cancer and high-risk adenomas) screening is aimed at detecting

Cutoff value determines the performance of a semi-quantitative immunochemical faecal occult blood test in a colorectal cancer screening programme

BACKGROUND: The cutoff of semi-quantitative immunochemical faecal occult blood tests (iFOBTs) influences colonoscopy referrals and detection rates. We studied the performance of an iFOBT (OC-Sensor) in colorectal cancer (CRC) screening at different cutoffs. METHODS: Dutch screening participants, 50-75 years of age, with average CRC risk and an iFOBT value >or=50 ng ml(-1) were offered colonoscopy. The detection rate was the percentage of participants with CRC or advanced adenomas (>or=10 mm, >or=20% villous, high-grade dysplasia). The number needed to scope (NNTScope) was the number of colonoscopies to be carried out to find one person with CRC or advanced adenomas. RESULTS: iFOBT values >or=50 ng ml(-1) were detected in 526 of 6157 participants (8.5%) and 428 (81%) underwent colonoscopy. The detection rate for advanced lesions (28 CRC and 161 with advanced adenomas) was 3.1% (95% confidence interval: 2.6-3.5%) and the NNTScope was 2.3. At 75 ng ml(-1), the detection rate was 2.7%, the NNTScope was 2.0 and the CRC miss rate compared with 50 ng ml(-1) was <5% (N=1). At 100 ng ml(-1), the detection rate was 2.4% and the NNTScope was <2. Compared with 50 ng ml(-1), up to 200 ng ml(-1) CRC miss rates remained at 16% (N=4). CONCLUSIONS: Cutoffs below the standard 100 ng ml(-1) resulted in not only higher detection rates of advanced lesions but also more colonoscopies. With sufficient capacity, 75 ng ml(-1) might be advised; if not, up to 200 ng ml(-1) CRC miss rates are acceptable compared with the decrease in performed colonoscopies

Immunochemical faecal occult blood test: number of samples and positivity cutoff. What is the best strategy for colorectal cancer screening?

Immunochemical faecal occult blood tests have shown a greater sensitivity than guaiac test in colorectal cancer screening, but optimal number of samples and cutoff have still to be defined. The aim of this multicentric study was to evaluate the performance of immunochemical-based screening strategies according to different positivity thresholds (80, 100, 120 ng ml−1) and single vs double sampling (one, at least one, or both positive samples) using 1-day sample with cutoff at 100 ng ml−1 as the reference strategy. A total of 20 596 subjects aged 50–69 years were enrolled from Italian population-based screening programmes. Positivity rate was 4.5% for reference strategy and 8.0 and 2.0% for the most sensitive and the most specific strategy, respectively. Cancer detection rate of reference strategy was 2.8‰, and ranged between 2.1 and 3.4‰ in other strategies; reference strategy detected 15.6‰ advanced adenomas (range=10.0–22.5‰). The number needed to scope to find a cancer or an advanced adenoma was lower than 2 (1.5–1.7) for the most specific strategies, whereas it was 2.4–2.7, according to different thresholds, for the most sensitive ones. Different strategies seem to have a greater impact on adenomas rather than on cancer detection rate. The study provides information when deciding screening protocols and to adapt them to local resources